Influences of performance parameters of GaAs/AlGaAs materials on photoemission
摘要
Photocathode based on GaAs/AlGaAs heterojunction has been applied broadly in night vision imaging intensifiers for its broad spectral response wavelength, high quantum efficiency and low dark current. Especially in recent years the extension of response wavelength to near infrared makes GaAs/AlGaAs applied in laser imaging. To obtain negative electron affinity GaAs photocathode with high performance, reasonable selection of performance parameters of GaAs material is required. In this paper on basis of photoemission model, analysis of the influences of diffusion length of minor carrier, recombination velocity at the interface of GaAs/AlGaAs and thickness of active GaAs layer on spectral response of GaAs photocathode were detailed, and the optimizing principle and methods of these parameters were proposed. Our measurement results of compositions distributions of GaAs/AlGaAs heterojunction are also given to demonstrate influences of material performance parameters.